As a selectable one-way clutch, known is such a selectable one-way clutch that a fixed plate where pawl members are provided protrudably, a rotational plate where recesses are formed for engaging with the pawl members respectively, and a selector plate provided between the mentioned two plates are provided on a shared axial line (the patent literatures 1 and 2). In such a clutch, the state of the pawl members is changed between a protrudable state and a restricted protrusion state by switching a rotational position of the selector plate, and thereby it is possible to select either a lock mode where torque transmission between the fixed plate and the rotational plate is allowed only at the time of a predetermined one rotational direction; or a free mode where the torque transmission between the plates is blocked at the time of both rotational directions.